1. Field of Invention
This invention relates to sewage distribution systems, specifically to an improved sewer relief valve.
2. Description of Prior Art
In the system of sewer pipes connecting residences and buildings with the city sewer line, problems will develop that will cause these lines to become clogged, thereby backing sewage and wastewater until the lines are filled and sewage overflows in the interior of a building. Conventional drain and sewer systems have no means to prevent this overflowing of sewage. This dilemma has motivated the development of a considerable amount of prior art with respect to deterring this overflowing sewage problem. Attempts to incorporate prior art into the conventional sewer system usually involved substituting prior art for the clean out plug of a sewage flow riser tube referred to as a clean out riser. In conventional sewer systems it is common to have at least one clean out riser to provide access to that system for maintenance purposes. The clean out riser is usually disposed vertically, has interior threads at its upper extremity, and is closed by an exteriorly threaded plug. These clean out plugs are manufactured in a variety of designs. One of the more common designs is a plug having extending wall portions generally referred to as a raised head plug, it being available from manufacturers such as Charlotte, Nibco, GSR, or American Brass. Comprising some form of a sewer relief valve that replaces the conventional raised head plug, prior art have made possible a partial solution to the dilemma. Prior art sewer relief valves function to relieve hydrostatic pressure in a sewer line at the clean out riser outside of a structure. The principle of operation behind said valve is, because said valve, installed at a level lower than all plumbing facilities inside a structure, forces sewage and wastewater from a plugged sewer line to discharge through means provided at said valve rather than inside said structure. Thus, no sewage can rise above the level of said valve installed in said conventional riser as it will automatically overflow on to the surrounding areas. As shown, prior art does provide a substantial measure of protection against sewage flooding any structure's interior. The amount of prior art work is somewhat extensive with many patents having been issued for devices which possibly offer solutions, at least in theory, to the sewer backup dilemma. However, no prior art models are readily available to all public or even contractors for installation in the conventional sewer system. As to why no prior art are readily available, the reasons are not obvious or apparent. A careful review of prior art suggests that these models are not appropriate for the following reasons:
(a) Due to technical difficulty and great expense of manufacturing a product, the product must be no more complicated than necessary in order for it to be cost effective. Some prior art are too complicated for the simple purpose that serve, and as a result are too costly and unfeasible for large scale production.
(b) Overly complicated prior art has the effect of making the product too expensive, reducing public demand and consequently public protection.
(c) Complicated prior art increases the level of difficulty of installation and requires professional assistance.
(d) Some prior art models have the disadvantage of obstructing the accessibility of the sewer system for maintenance purposes, such as: U.S. Pat. No. 4,475,571 to Houston, May 1984; and U.S. Pat. No. 4,114,641 to Robinson, September 1978.
(e) Furthermore, weather and age severely inhibit removal of fittings not prepared and designed for occasional removal. As a result, the fitting is often destroyed in the attempt to remove it.
Obviously, even though prior art has been developed and patented, their failure to protect the general public from certain financial and possible health risks as a result of sewage flooding the interior of a building unprotected by a sewer relief valve, demands the need for a new, cost effective and uncomplicated sewer relief valve. This need can be satisfied by the following improved sewer relief valve. This invention utilizes an assembly which replaces only the raised head clean out plug, said assembly having a closure which is adapted to open at a predetermined level of hydrostatic pressure.